Extended band two-folded orthogonal mode microwave transducer devices and methods

Abstract

Satellite networks play an important role in many applications due to their unique features of global coverage and mobility assistance. Low Earth Orbit (LEO) satellites are currently gaining popularity in wireless communications as they will be heavily used in future wireless communication networks. To enable polarisation diversity, satellite systems commonly use dual-polarized antennas where orthomode transducers (OMTs) are employed in such systems to feed the antennas with the two orthogonal polarizations. An OMT should provide high impedance matching, high isolation levels between ports as well as being lightweight and compact. OMT designs are presented providing a bandwidth ratio of about 55% with good impedance matching and high isolation compatible with LEO satellite feeding structures in terms of thermal, power, and passive intermodulation analysis.

What is claimed is: 
     
         1 . A device comprising:
 a first element comprising an input port, a junction and four output ports in a plane wherein a microwave signal within a predetermined frequency range coupled to the input port is split into a first polarisation which is coupled to a first pair of the four output ports which are disposed on either side of junction along a first axis and a second polarisation which is coupled to a second pair of the four output ports which are disposed on either side of junction along a second axis where the first axis is orthogonal to the second axis;   a first arm of a combining network comprising;
 a first combiner comprising a pair of first ports coupled to one of the first pair of the four output ports and the second pair of the four output ports and a second port coupled to the pair of first ports; 
 a waveguide twist coupled at one end to the second port of the first combiner and at a second distal end to a first offset waveguide; and 
 the first offset waveguide; and 
   a second arm of the combining network comprising:
 a second combiner comprising another pair of first ports coupled to the other of the first pair of the four output ports and the second pair of the four output ports and another second port coupled to the pair of first ports where the each first port of the another pair of first ports is coupled to an output port of the other of the first pair of the four output ports and the second pair of four output ports by a second offset waveguide; 
 the two second offset waveguides; and 
 another waveguide twist coupled at one end to the another second port of the second combiner and at a second distal end of the another waveguide twist to an end of a waveguide. 
   
     
     
         2 . The device according to  claim 1 , wherein
 the junction is a turnstile junction comprising a series of stepped cylinders;   an upper stepped cylinder of the series of stepped cylinders is disposed towards the input port;   the series of stepped cylinders have increasing diameters from the upper stepped cylinder of the series of stepped cylinders and are disposed along an axis away from the input port.   
     
     
         3 . The device according to  claim 1 , wherein
 each output port of the four output ports is a half-height rectangular waveguide.   
     
     
         4 . The device according to  claim 1 , wherein
 the distal end of the waveguide and a distal end of the first offset waveguide are aligned along a common plane.   
     
     
         5 . The device according to  claim 1 , wherein
 each output port of the four output ports is a half-height rectangular waveguide;   the pair of first ports of the first combiner, the two second offset waveguides and the another pair of first ports of the second combiner are half-height rectangular waveguides;   the second port of the first combiner and the another second port of the second combiner are a full-height rectangular waveguides; and   the waveguide twist, the another waveguide twist and the first offset waveguide are full-height rectangular waveguides.   
     
     
         6 . The device according to  claim 1 , wherein
 each output port of the four output ports is a half-height rectangular waveguide;   the pair of first ports of the first combiner, the two second offset waveguides and the another pair of first ports of the second combiner are half-height rectangular waveguides;   the second port of the first combiner and the another second port of the second combiner are a full-height rectangular waveguides;   the waveguide twist, the another waveguide twist and the first offset waveguide are full-height rectangular waveguides; and   the full-height rectangular waveguide of the distal end of the waveguide and the full-height rectangular waveguide at a distal end of the first offset waveguide are aligned along a common plane.   
     
     
         7 . The device according to  claim 1 , wherein
 the junction is a turnstile junction comprising a series of stepped cylinders;   an upper stepped cylinder of the series of stepped cylinders is disposed towards the input port;   the series of stepped cylinders have increasing diameters from the upper stepped cylinder of the series of stepped cylinders and are disposed along an axis away from the input port;   each output port of the four output ports is a half-height rectangular waveguide;   the pair of first ports of the first combiner, the two second offset waveguides and the another pair of first ports of the second combiner are half-height rectangular waveguides;   the second port of the first combiner and the another second port of the second combiner are a full-height rectangular waveguides;   the waveguide twist, the another waveguide twist and the first offset waveguide are full-height rectangular waveguides; and   the full-height rectangular waveguide of the distal end of the waveguide and the full-height rectangular waveguide at a distal end of the first offset waveguide are aligned along a common plane.   
     
     
         8 . A method comprising:
 providing a first element comprising an input port, a junction and four output ports in a plane wherein a microwave signal within a predetermined frequency range coupled to the input port is split into a first polarisation which is coupled to a first pair of the four output ports which are disposed on either side of junction along a first axis and a second polarisation which is coupled to a second pair of the four output ports which are disposed on either side of junction along a second axis where the first axis is orthogonal to the second axis;   providing a first arm of a combining network comprising;
 a first combiner comprising a pair of first ports coupled to one of the first pair of the four output ports and the second pair of the four output ports and a second port coupled to the pair of first ports; 
 a waveguide twist coupled at one end to the second port of the first combiner and at a second distal end to a first offset waveguide; and 
 the first offset waveguide; and 
   providing a second arm of the combining network comprising:
 a second combiner comprising another pair of first ports coupled to the other of the first pair of the four output ports and the second pair of the four output ports and another second port coupled to the pair of first ports where the each first port of the another pair of first ports is coupled to an output port of the other of the first pair of the four output ports and the second pair of four output ports by a second offset waveguide; 
 the two second offset waveguides; and 
 another waveguide twist coupled at one end to the another second port of the second combiner and at a second distal end of the another waveguide twist to an end of a waveguide. 
   
     
     
         9 . The method according to  claim 8 , wherein
 the junction is a turnstile junction comprising a series of stepped cylinders;   an upper stepped cylinder of the series of stepped cylinders is disposed towards the input port;   the series of stepped cylinders have increasing diameters from the upper stepped cylinder of the series of stepped cylinders and are disposed along an axis away from the input port.   
     
     
         10 . The method according to  claim 8 , wherein
 each output port of the four output ports is a half-height rectangular waveguide.   
     
     
         11 . The method according to  claim 8 , wherein
 the distal end of the waveguide and a distal end of the first offset waveguide are aligned along a common plane.   
     
     
         12 . The method according to  claim 8 , wherein
 each output port of the four output ports is a half-height rectangular waveguide;   the pair of first ports of the first combiner, the two second offset waveguides and the another pair of first ports of the second combiner are half-height rectangular waveguides;   the second port of the first combiner and the another second port of the second combiner are a full-height rectangular waveguides; and   the waveguide twist, the another waveguide twist and the first offset waveguide are full-height rectangular waveguides.   
     
     
         13 . The method according to  claim 8 , wherein
 each output port of the four output ports is a half-height rectangular waveguide;   the pair of first ports of the first combiner, the two second offset waveguides and the another pair of first ports of the second combiner are half-height rectangular waveguides;   the second port of the first combiner and the another second port of the second combiner are a full-height rectangular waveguides;   the waveguide twist, the another waveguide twist and the first offset waveguide are full-height rectangular waveguides; and   the full-height rectangular waveguide of the distal end of the waveguide and the full-height rectangular waveguide at a distal end of the first offset waveguide are aligned along a common plane.   
     
     
         14 . The method according to  claim 8 , wherein
 the junction is a turnstile junction comprising a series of stepped cylinders;   an upper stepped cylinder of the series of stepped cylinders is disposed towards the input port;   the series of stepped cylinders have increasing diameters from the upper stepped cylinder of the series of stepped cylinders and are disposed along an axis away from the input port;   each output port of the four output ports is a half-height rectangular waveguide;   the pair of first ports of the first combiner, the two second offset waveguides and the another pair of first ports of the second combiner are half-height rectangular waveguides;   the second port of the first combiner and the another second port of the second combiner are a full-height rectangular waveguides;   the waveguide twist, the another waveguide twist and the first offset waveguide are full-height rectangular waveguides; and   the full-height rectangular waveguide of the distal end of the waveguide and the full-height rectangular waveguide at a distal end of the first offset waveguide are aligned along a common plane.